The present invention relates to a bucket for holding specimens in a centrifugal separator while the specimens are subjected to centrifugal separation, and more particularly to such a bucket for use with a swing-type rotor.
For centrifugal separation of specimens, the specimens are placed in test tubes held by one holder which is housed in a bucket. The bucket is swingably suspended from a swing-type rotor that will be rotated at high speed for separating the specimens under centrifugal forces. When a relatively large quantity of specimens are to be separated, they are put in a specimen bottle directly accommodated in the bucket. The bucket is also swingably suspended from the swing-type rotor that will be rotated at high speed for separating the specimens under centrifugal forces.
The holder for holding test tubes has a rectangular-parallelepiped shape or a cylindrical shape, and the specimen bottle has a tubular shape or a hollow rectangular parallelepiped shape. The bucket is required to hold the holder or the specimen bottle stably so that the test tubes or the specimen bottle will not be broken and the separated specimens will not be disturbed. To meet such a requirement, a bucket for accommodating a rectangular-parallelepiped-shaped holder or a hollow rectangular-parallelepiped-shaped specimen bottle therein has heretofore been complementarily box shaped so that the holder or the specimen bottle will snugly fit in the bucket. Similarly, a bucket for accommodating a cylindrical holder or a hollow cylindrical or tubular specimen bottle therein has heretofore been complementarily cylindrical in shape so that the holder or the specimen bottle will snugly fit in the bucket. The cylindrical bucket is disclosed in U.S. Pat. Nos. 4,009,824 and 4,032,066, and the box-shaped bucket is shown in U.S. Pat. Nos. 4,141,489 and 4,147,494. Therefore, it has been customary practice to have two kinds of buckets, box-shaped and cylindrically shaped, in readiness for use, and to change the buckets, if necessary, to meet the shape of a holder or specimen bottle to be used, a procedure which has been tedious and time-consuming.
The bucket has heretofore been fabricated by cutting a heat-treated and forged block of aluminum. More specifically, the fabrication process has included the steps of preparing a bucket in the form of an aluminum casting, partly cutting the bucket, heat-treating the bucket to increase its mechanical strength, and treating the surface of the bucket to enhance corrosion resistance. The bucket is therefore expensive to manufacture, and a plurality of such expensive buckets have been required by one centrifugal, as described above. Where a bucket comprises a casting, it tends to have internal defects that are difficult to detect in advance. If any defective bucket is used, the centrifugal separator suffers from the danger of getting broken during operation.